nicehash was actually what i had in mind, but what’s the difference between that and mining?
It's a mining pool. The chances of you mining a block on your own are infinitesimally small nowadays, so many people 'pool' together to try and mine a block. When one person in the pool mines a block, the reward is split between all the pool participants based on how much work they contributed that period.
If you're actually interested in mining bitcoin specifically, the bitcoin.com pool has the highest payouts of any pool. You're not very likely to make money mining off GPU hardware, though. Mining is dominated by ASICs.